Healthline: What we know about breakthrough monkeypox cases
UC expert says people with certain medical conditions may be less likely to be protected
The World Health Organization announced recently that breakthrough infections have been reported in people who had been vaccinated against monkeypox. Healthline reported there is limited data available on the efficacy of the JYNNEOS shot, so it will take time to understand how effective it is at preventing infection. Data from the 1980s has shown that the vaccine was at least 85% effective, however, some health experts expect that number to change in the current outbreak. One of the experts cited in the Healthline story was Carl Fichtenbaum, MD, of the Division of Infectious Diseases at the UC College of Medicine.
Carl Fichtenbaum, MD, of the Division of Infectious Diseases at the UC College of Medicine/Photo/Joe Fuqua II/UC Marketing + Brand
Fichtenbaum says that the vaccine has not been tested in humans to a large extent, so 85% is really a ballpark estimate.
Healthline reported the strength of people’s immune systems varies and certain individuals may not mount a strong enough immune response to avoid getting sick even if they are fully immunized.
“As always, those with immunosuppression, cancer, transplant patients, and persons with HIV who have a lower CD4+ lymphocyte count below 350 cells/mm3 would be more likely to not respond as well to vaccine and have a breakthrough infection,” Fichtenbaum said.
People older than 60 are also likely to be less protected, Fichtenbaum added.
Fichtenbaum says we are still learning about how common breakthrough infections are, and we don’t have the best track record for preventing the spread of infectious diseases during public health emergencies.
“Time will tell how many breakthroughs occur,” Fichtenbaum said.
Next Lives Here
The University of Cincinnati is classified as a Research 1 institution by the Carnegie Commission and is ranked in the National Science Foundation's Top-35 public research universities. UC's graduate students and faculty investigate problems and innovate solutions with real-world impact. Next Lives Here.
Related Stories
Driven by curiosity, guided by care
May 14, 2026
Max Wilson, a University of Cincinnati College of Allied Health Sciences health sciences major on the pre-physician assistant track, found his path expanding beyond the classroom and into hands-on research focused on human performance and patient care.
New cohort of nursing students get ready to join co-ops
May 14, 2026
A new chapter is beginning for more than 100 University of Cincinnati College of Nursing rising seniors as they embark on one of the most distinctive experiences in undergraduate nursing education: the UC Nursing Co-op Program. The incoming cohort will fan out across Cincinnati's premier healthcare institutions, stepping into some of the most dynamic and specialized clinical environments in the region. Placement sites include UC Medical Center (UCMC), West Chester Hospital, Cincinnati Children's Hospital Medical Center (CCHMC) Burnet, College Hill, and Liberty campus.
Will a gas tax help lower prices at the pump?
May 14, 2026
WCPO recently reported on Kentucky and Indiana’s steps to combat surging gas prices, cutting and suspending state gas taxes, respectively. UC economist Michael Jones explained the impact on Cincinnati.